This invention relates in general to a static discharge device for preventing an electrostatic shock caused when a human body contacts with ground body such as a door-knob. More specifically the present invention provides an automotive vehicle ignition key having an arrangement for minimizing electrostatic discharge shock to a user.
It is well known that when a person leaves a vehicle after driving, he may have been charged with electricity and therefore receive an electrostatic shock when he touches an inside door knob grounded to vehicle chassis.
It was previously proposed to prevent such shock by providing a suitable resistance material between a human body which was a chargeable body and a ground body so that current flow was restricted.
However, according to experiments, it was ascertained that the electrostatic shock which a person feels was not only decided by the magnitude of an electric current flowing through him. Rather it was more painful for him to discharge through a pointed part of his body (for example finger tip) rather than to discharge through a flat part of his body (for example palm). A person feels more pain when the electric discharge energy concentrates on the pointed part, even if the total electric charge is the same.
According to the experiment conducted by the inventors, it became clear that, with respect to a current waveform produced when a person discharges the electric charge generated in his body through a minute air gap, peak value is reduced to a fraction of what it would otherwise be and the electric shock was reduced so much in the case of holding the resistance element having a certain resistance with fingers so as to increase the contacting area relative to the case of touching the ground body with the finger tip.